This disclosure relates to electronic mobile devices. In particular, this disclosure relates to hinge structures for cellular phones.
Some types of electronic mobile devices such as cellular phones, personal digital assistants (PDAs), and the like include a “flip” or pivotable cover connected to a base. These flip devices are popular for various reasons; for example, a display is typically supported by the cover and a keypad or other input panel is supported by the base. Therefore, both the display and the keypad can be larger than those of similarly-sized non-flip devices that include a display and a keypad on a single surface. As another example, the cover closes against the keypad when the mobile device is not in use, thereby preventing unintentional selection of keypad buttons. Furthermore, moving the cover of some electronic mobile devices causes the device to perform different actions, such as answering calls, ending calls, or de-energizing a main display to enter a power-saving mode.
Most previous flip devices include a hinge structure to pivotally connect the cover and the base. The hinge includes a shaft that defines a hinge axis and supports one end of a compression spring. The other end of the spring engages a set of cams that pivot relative to one another about the hinge axis. A first cam is supported by the base, and a second cam is supported by the cover. The engaging surfaces of the cams are shaped such that the spring biases the cams to positions in which the cover is fully closed or fully open. That is, the spring and the engaging surfaces of the cams are designed such that the cover is forced away from partially open positions. As such, the hinge assists a user in both opening and closing the cover.
Unfortunately, the hinge may be worn out with repeated and frequent use. For example, the spring may deform and the characteristics of the spring may change due to compressive forces applied as the cover pivots. As such, the biasing force provided by the hinge may decrease over the life of the device. Furthermore, typical hinge structures are relatively tall compared to other components of electronic mobile devices and therefore, in many cases, flip devices cannot be made as thin as non-flip devices.